Device for locating picture plates in succession so as to be substantially normal to the light path of lighting apparatus



April 15, 1952 VAN ALPHEN 2593,076

7 DEVICE FOR LOCATING PICTURE PLATES IN SUCCESSION 50 AS TO BE SUBSTANTIALLY NORMAL TO THE LIGHT PATH OF LIGHTING APPARATUS Filed July 8, 1946 IN V[ N 7' 0R P/[Tffi MART/NUS VAAMLPHEN ar/f Patented Apr. 15, 1952 LY NORMAL TO THE LIGHT PATH F LIGHTING APPARATUS Pieter Martinus van Alphen, Eindhoven, Netherlands,- assignor to Hartford National Bank and Trust Company,'Hartford, C0nn., as trustee Application July 8, 1946, Serial No. 681,986 In the Netherlands January 18, 1943 Section 1, Public Law GBILAugust s, 1946 Patent'expires January 18, 1963 When projecting small picture-plates, for examplediapositives and-negatives, use is generally made of a carrier in which two. or more plates canbe inserted. By shifting the separately movable plates it is possible to locate them in succession so as to be substantially normal to the light path of lighting apparatus. This device has several disadvantages. Thus,'for example, a regular succession is generally out of the question so that for a considerable time an image is not projected. In addition a hand of the operator of the lighting apparatus may be repeatedly in the light path with the result that the attention of the public is distracted from the image formed on the screen.

The device according to the invention, which obviates these difiiculties, is characterizedin that at least one plate carrier is adapted to rotate on a first spindle, whereas at least one other plate carrier isadapted to rotate on a second spindle,

said spindles being parallel to each other and so spaced apart that when the device cooperates with lighting apparatus the two spindles are outside the light path. In this device shifting the plates back and forth is omitted and on being inserted in the carrier and rotated they directly occupy the correct position in the light path.

One form of construction of the device according to the invention is characterized in that alternately a plate carrier adapted to rotate on the firstspindle and a plate carrier adapted to rotate on the second spindle are substantially normal to the light path. The insertion of the plates is thus facilitated.

A further form of construction of the device according to the invention is characterized in that the rotations of the two spindles are coupled. Owing to this coupling the operator of the device gets his hands slightly free and this still further assists the regular exchange of the images.

In the first form of construction of the device according to the invention this coupling is carried out in such manner that if a plate carrier which is outside the light path is moved into the light path the carrier which was originally normal to the light path is removed from its operative position by means of a projecting lug seated on one of the carriers and acting on or being acted on by the other carrier. V

The plate which is moved into the light path throws initially a most unsharply defined blurred image on a screen; during the rotation this image becomes more and more sharply defined and is at full definition when the plate has reached the operating position, During the beginning of this rotation another plate occupies the operative posi- 2 Claims. (Cl. 8828) V I 2 e I tion and is consequently pictured in a sharply defined manner. This plate is removed from the operative position after the projecting lug seated on one of the carriers has come into contact with the other carrier. Consequently, the plate becomes less sharply definedby and by. With this manner of coupling the images so to say melt into each other andthis makes an agreeable impres sion on. the spectators, particularly in the case of coloured picture-plates.

The second form of construction of the device according to the invention is characterized in that the rotations of the two spindles are coupled by means of a hinged rod system, each spindlehav in'gsecuredfto it a rod of the said system; Such 'a coupling may be adjusted for example in such manner that the images of those circumscribings of two successive plates that are parallel to the axes of rotation but are most remote from them coincide approximately; An uninterrupted row of images not overlapping each other is thus set In order that the invention may be clearly understood and readily carried into effect it will now be described more fully with reference to the accompanying drawing.

Figure 1 is a functional schematic side view of one arrangement of two picture-plates arranged in front of a light projecting lens of a projection machine; and

Figure 2 is a similar view of another modification or arrangement of the two picture-plates.

Referring to Figure 1, O designatesthe optical system ofa lighting apparatus in front of which is arranged a device according to the invention which comprises plate carriers I and 2 with the respective'axes of rotation 3 and 4. On its lateral side the carrier I is fitted with a projecting lug 5. .On the carrier I being rotated in the direction of the'arrow 6 the lug 5, in the dotted position of the carrier engages the carrier 2 which occupies the operative position. This carrier is then removed from the operative position in the direction of the finally caused to bear on stops I0 and II formed as small rubber blocks.

i Referring to Figure 2, in which 0 again-desig- 3 nates the optical system of a lighting system, the carriers 2| and 22 of the device are coupled by means of a rod 21 which at the points 25 and 26 is articulated to the carriers 2| and 22. In this case, the part of the lateral side of the carrier 2| between the points 23 and 25 and also the part of the lateral side of the carrier 22 between the points 24 and 26 consequently serve as rods of the articulated rod system.

What I claim is:

1. In a projection apparatus for projecting a light beam along an optical axis, a combination of two cooperating picture plate carriers respectively pivoted at two first points each on an opposite side of the optical axis and movable to focusing position transversely of the axis, spring means for each carrier, each said spring means having one end thereof anchored at a second point each spaced from said first pivot point of said carrier operatively associated therewith and another end of each said spring means being secured to a projection on the associated plate carrier for acting as an over-center toggle to hold the associated plate carrier in either of two predetermined positions, one of which is said focusing position, and a projecting element on one of said carriers for engaging the other of said carriers so that movement of either of said carriers to said focusing position when the other of said carriers is in said focusing position will force the other of said carriers sufiiciently out of said fcusingposition to move said spring means of the other of said carriers over-center to a position where said spring means can then turn the other of said carriers entirely out of the path of said light beam.

2. Ina projection apparatus for projecting a light beam along an optical axis, a combination of two cooperatingpicture plate carriers respectively pivoted at two first points each on an oppocenter toggle to hold the associated plate carrier in either of said two positions, and a projecting element on one of said carriers for engaging the other of said carriers so that movement of either of said carriers to said focusing position when the other'of said carriers is in said focusing position will force the other of said carriers sumciently out of said focusing position to move said spring means of the other of said carriers over-center to a position where said spring means can-then turn the other of said carriers entirely out of the path of said light beam and into said second position.

PIETER MARTINUS VAN ALPHEN,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 750,711 Shea Jan. 26. 1904 914,728 Keller Mar. 9, 1909 958,370 Currie May 17, 1910 964,350 Welsh July 12, 1910 FOREIGN PATENTS Number Country Date 617,627 France Nov. 22, 1926 244,093 Switzerland Mar. 1, 1947 

